That’s the way Oracle On Demand works, this won’t work under other environments.
Skip this step if you are not using oracle on demand.
otherwise enter the command as
pbrun impdba -u <ur instance name like abprod>.

I have managed to re-write my shell with vi, I have
then made sure that the permissions on the file are correct, then formed a soft link with the fndcpesr command,
then defnied it as an executable,
then defined it as a concurrent program,
then added it to a request set and ran it but am still getting the same error message that the executable cannot be ran,